The invention relates to an automatic pull-in mechanism for drawer guides; with a guide rail formed of sheet metal which is to be fastened to the carcase wall, which has a portion of its profile bent upwardly from a profile portion projecting at substantially right angles and horizontally from the carcase wall and entering from below into the corresponding runner rail formed by an open-bottomed hollow member which is to be fastened removably on the drawer, on which tracks are formed in the interior of the runner rail for rolling bearings mounted in an elongated cage, which can roll on the tracks of the guide rail on the one side and on tracks formed by associated portions of the inner surface of the runner rail, and thus permit a longitudinal displacement of the runner rail relative to the guide rail.
In addition to the roller drawer guides provided with rollers rotatably mounted on the guide rail and runner rail, such rolling bearing-mounted drawer guides have in recent times become widely used for the mounting of drawers in the corresponding cabinet, because the drawers are very easy to close and open even when bearing heavy weights. Precisely this easy running of such drawer guides, however, also has the disadvantage that a closed drawer can very easily be slightly opened accidentally, for example when an article of clothing on a person passing the cabinet catches on it. Also, when a drawer is shut forcefully and the drawer front collides with the carcase, a reaction occurs which again slightly opens the drawer. It has even been seen that, when a drawer is closed rapidly, it compresses the air trapped in the carcase interior and the displaced air then produces an opening thrust against the back of adjacent drawers, which, again on account of the easy running of the drawer guide, slightly opens the adjacent drawer. Therefore there is an urgent need to construct drawer guides such that as the drawer they are carrying approaches the closed position they will positively draw it into the fully closed position and hold it there with a closing force, even if slight, in order to prevent the effects described above. In the case of the roller drawer guides mentioned above, such a pulling-in action can be produced relatively simply by the weight of the drawer itself, by tilting slightly downwardly the portions of the guide rail or runner rail on which the rollers of the other rail run as they approach the closed position. When such a downwardly tilted portion of the rail is reached, a component of the weight force develops toward the carcase interior and pulls the drawer in. In drawer guides of the kind mentioned above, however, such a function cannot be realized, because the runner rail's support on the guide rail is provided by the roller bodies carried in cages and the runner rail completely surrounds the tracks of the guide rail. The ball races of the cooperating rails must therefore be made precisely rectilinear. The problem of the accidental opening of a closed drawer by catching or by the air-pumping effect of the closing of another drawer has been partially solved by providing catch means which act between the rails of the guides when the closed position is reached, because, for example, a resilient body, e.g., a wheel of elastomeric plastic, is mounted on one rail, preferably the guide rail, whose circumference, immediately before reaching the closed position, strikes against a projection or abutment provided fixedly on the other rail, i.e., the runner rail in this particular case. If an additional closing pressure is then exerted on the drawer toward the fully closed state, the resilient body, i.e., the resilient wheel, is first compressed radially until, in a dead center position, a maximum compression takes place. When this dead center is passed, the wheel resiliently returning to its original shape thrusts against the projection or abutment and, through the runner rail affixed to it, pushes the drawer into the closed position. Catch means of this kind or of similar or conceivable kinds, operating for example with ball catches or magnetic catches, have the disadvantage that they cannot become effective until just ahead of the closed position of the drawer, and then require an additional, greater exertion of pressure on the drawer in order to hold it in the closed position.